JPS59229010A - Exhaust valve driving device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce an amount of oil consumed so that an exhaust valve is kept in a closed state, by a method wherein a hydraulic block is arranged so that it can be freely drawn out and inserted from and into the space between the upper end of the valve rod of an exhaust valve, which is of an opening-out type and is hydraulically controlled, and a stationary wall above the valve rod. CONSTITUTION:An exhaust valve 40, being of an opening-out type, is located between a combustion chamber 10 and an exhaust gas passage 19, and a piston 41 attached to a valve rod is disposed in a cylinder. Through control of electromagnetic valves 71, 72, 73 and 74, oil is supplied from a pressure accumulator 55, which stores high-pressure oil, to a valve opening oil chamber 42 and a valve closing oil chamber 42 to control the exhaust valve 40. When the exhaust valve 40 is closed, a hydraulic block 81 is interposed between the upper end of the valve rod and a stationary wall 44 through the working of a hydraulic cylinder 91, and simultaneously, high-pressure oil is supplied in the block 81 through a felxible tube 85 to hold the exhaust valve 40 in a closed state against the pressure in a combustion chamber 10. In opening of the valve, the block 81 is drawn out, resulting in the possibility to raise the valve.

Description

[Detailed description of the invention] The present invention relates to an exhaust valve drive device for an internal combustion engine.

The first exhaust valve hydraulic drive system for a conventional two-stroke internal combustion engine
As shown in the figure. In the figure, a piston 12 reciprocates inside a cylinder block 11, and an exhaust valve 13 is mounted on a bush 1 at the top.
An exhaust valve box 15 that is held by 4 is provided. piston 12
The upper part of the combustion chamber 10 is a combustion chamber, and the exhaust valve box 15 is provided with an exhaust passage 19 from the exhaust valve 13. The exhaust valve 13 has a valve spring 1
6 and a hydraulic piston 18 that slides within a hydraulic cylinder 17 is attached. High-pressure hydraulic oil is supplied to the hydraulic cylinder 17 from a hydraulic pump 22 via a high-pressure pipe 21 . Here, the roller 33 is driven by the cam 32 attached to the camshaft 31, and the syringer 23 of the hydraulic pump f22 is further driven. A spring 34 is provided on the roller 33. As shown in FIG. 1, the exhaust valve 13 is closed by a valve spring 16, and the roller 33 is pressed against the cam 32 by a spring 34. Now, when the camshaft 31 rotates and the cam 32 pushes up the roller 33, the plunger 23 rises and compresses the hydraulic oil in the hydraulic cylinder 7°22. Therefore, the pressure of the hydraulic oil in the hydraulic cylinder 17 increases via the high-pressure pipe 21, and a force that opens the exhaust valve 13 downward acts on the hydraulic piston 18. Changes in the pressure P of the hydraulic oil in the hydraulic cylinder 17 and the pressure L of the exhaust valve 13 at this time are shown in FIG. 2 with the crank angle as the horizontal axis. As the plunger 23 rises, P rises to a pressure P1 that matches the setting force of the valve spring 16. Furthermore, plunger 2
3 increases, and when the pressure of the hydraulic oil reaches P2, which matches the pressure of the working gas in the combustion chamber 10 at the crank angle θl, the exhaust valve 1
3 begins to open. If the exhaust valve 13 continues to open, the combustion chamber 1
As the working gas in the combustion chamber 10 flows out into the exhaust passage 19, the working gas pressure in the combustion chamber 10 decreases, and the working gas pressure in the exhaust passage 19 increases, and the difference between the two becomes smaller. When the pressure also decreases and the pressures of the two working gases become equal at θ2, the exhaust valve 13 is opened with the pressure of the working oil corresponding to compressing the valve spring 16. When the camshaft 31 further rotates and the plunger 23 begins to descend, the pressure of the hydraulic oil in the hydraulic cylinder 17 begins to decrease.
Due to the force of the valve spring 16, the exhaust valve 13 begins to close. The exhaust valve 13 finishes closing at the crank angle θ3 at which the pressure P of the hydraulic oil returns to the pressure P1 that matches the set force of the valve spring 16.

However, the above method has the following drawbacks.

In FIG. 2, the pressure of the hydraulic oil corresponding to the force of the valve spring 16 is shown by a dashed line. The shaded area in FIG. 2 is the work of the granger 34 required to drive the exhaust valve 13 against the pressure difference between the working gas in the combustion chamber 10 and the exhaust passage 19 that acts on the exhaust valve 13.

That is, in the conventional exhaust valve hydraulic drive system, the camshaft must perform this amount of work, which worsens the fuel consumption rate of the engine.

Next, it is necessary to generate a working oil pressure P2 in the granger 23 that matches the working gas pressure in the combustion chamber 10 shown in FIG. 2, which requires a large camshaft 31 and cam 32. Further, since the cam 32 is fixed to the camshaft 31, it is not possible to change the phase of the cam and change the opening/closing timing of the exhaust valve 13 while the two engines are operating.

The purpose of the present invention is to focus on the above points, and to improve the camshaft and □
The present invention aims to provide an exhaust valve drive device that eliminates the cam device, simplifies the structure, reduces power consumption of the hydraulic drive device, and can change the opening/closing timing of the exhaust valve during operation using electronic control. These include an exhaust valve that opens outward toward the outside of the combustion chamber, a fluid pressure cylinder in which a piston is inserted in the middle of the valve stem of the exhaust valve, and the fluid pressure cylinder 1. ] A solenoid valve that is installed in each of the supply path and discharge path of high-pressure fluid to the cylinder and controls the opening and closing of each path.

During the closing period of the exhaust valve, a hydraulic block is provided which is held between the fixed wall provided on the upper part of the exhaust valve rod and the upper end of the exhaust valve rod by the force of the high-pressure fluid.

The present invention is applicable to internal combustion engines and reciprocating compressors.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is an explanatory diagram showing an exhaust valve driving device according to one embodiment of the present invention.

In the figure, the exhaust valve 40 is of an outward-opening type that opens when raised upward, and a pressure receiving collar 41. That is, install the piston. The lower part of the pressure receiving collar 41 is a solenoid valve 71
The upper part of the pressure receiving collar 41 is an open valve oil chamber 42 into which hydraulic oil from the high pressure oil supply pipe 51 flows through, and the closed valve oil chamber 4 into which hydraulic oil from the high pressure oil supply pipe 51 flows through an electromagnetic valve 73.
It is 3.

An insertable hydraulic block 81 is provided between the upper end of the exhaust valve rod and the fixed wall 44, and is moved by a hydraulic cylinder 91 into which hydraulic oil from the high-pressure oil supply pipe 51 flows through the electromagnetic valve 75. Further, the hydraulic oil from the high-pressure oil supply pipe 51 is applied to the hydraulic block 81 through the electromagnetic valve 77 and the flexible pipe 85.

Hydraulic oil is stored in the hydraulic oil tank 53.

High-pressure hydraulic oil is supplied to a pressure accumulator 55 by a hydraulic bonder 54 driven by a motor or an engine crankshaft.

High pressure hydraulic oil flows from the pressure accumulator 55 into the high pressure oil supply pipe 51 . Open valve oil chamber 42. Closed valve oil chamber 43. Return oil from the hydraulic cylinder 91 and the hydraulic block 81 is supplied to the solenoid valve 72.
74, 76, and 78, and is collected in the return pipe 52 and reaches the hydraulic oil pump 53.

Also, solenoid valves 71, 72, 73, 74, 75° 76.77
．． 78 is opened and closed by the output electric signal from the controller 61, and the controller 61 receives the engine crank angle signal 6.
2 is done manually.

Here, the details of the movement system of the hydraulic pressure roller 81 are shown in FIG.

The hydraulic block 81 is the hydraulic piston 9 of the hydraulic cylinder 91.
2 and rotates around a fulcrum 84.
mounted on. When high-pressure hydraulic oil does not act on the hydraulic cylinder 91, the hydraulic piston 92 is returned by the expanding force of the spring 93, and accordingly, the hydraulic block 8
1 also returns to its original position.

Furthermore, the detailed structure of the hydraulic block 81 is shown in FIG. 5.

A hydraulic disk 82 is moved within the hydraulic block 81 by high-pressure hydraulic oil from a flexible pipe 85. When the pressure of the hydraulic oil in the foot 2 drops, the hydraulic disk 82 is pushed back by the force of the spring 86.

By the way, the fixed wall 44 has a hole 45 through which the upper part of the valve stem of the exhaust valve 40 can pass, and the hydraulic block 81 is made larger in diameter than the hole 45.

The operation in the case of the above configuration will be described.

As shown in FIG. 3, when the exhaust valve 40 is closed, the output signal from the controller 61 causes the solenoid valve 74 to close, the solenoid valve 73 to open, and high-pressure hydraulic oil acts on the closed valve oil chamber 43 to exhaust air. Valve 40 is closed.

Therefore, when the change in the cylinder internal pressure P2 with respect to the crank angle θ of the engine is investigated, it is found as shown in FIG.

When the exhaust valve 40 closes at the crank angle θ4, the gas cylinder 1
2, the working gas in the cylinder begins to be compressed, and the pressure P2 begins to increase. Top dead center TDC of piston 12
Since fuel is injected into the working gas in the combustion chamber 10 nearby and combusted, lP2 becomes the maximum pressure Pmax. Thereafter, P2 decreases as the piston 12 descends. crank angle θ
At 5, the exhaust valve begins to open and Pz further decreases.

FIG. 6 also shows the rift L of the exhaust valve 40 and the hydraulic pressure Po acting on the hydraulic cylinder 91.

As shown in FIG. 6, immediately after the exhaust valve 40 is closed at θ4, the solenoid valve 76 is closed by the output signal from the controller 61, and the solenoid valve 75 is opened. As a result.

High-pressure hydraulic oil is supplied to the hydraulic cylinder 91, the hydraulic piston 92 moves, and the hydraulic block 81 is set between the upper part of the valve stem of the exhaust valve 40 and the hole 450 of the fixed wall 44 shown in FIG. Subsequently, the stain control valve 78 is closed by the output signal from the controller 61, the solenoid valve 77 is opened, high-pressure hydraulic oil is supplied to the hydraulic block 81 through the flexible pipe 85, and the hydraulic disc 82 is extended upward. , fixed wall 4
4 as a base, press the exhaust valve 40 onto the valve seat. As a result, the crank angle θ further advances, Pz increases, and Pr
Even if the temperature reaches rlax, the exhaust valve 40 will not be pushed upward by PmaX and will not open.

Immediately before the exhaust valve starts opening θ5 in FIG. 6, the solenoid valve 78 is opened by the output signal of the controller 61.

Close the solenoid valve 77. As a result, the hydraulic pressure of the hydraulic block 81 is lowered, and the hydraulic disc 82 is lowered by the force of the spring 86.
shrinks downward. Subsequently, the solenoid valve 76 is opened, and the solenoid valve 7
5 is closed to lower the working pressure of the hydraulic cylinder 91, the hydraulic piston 92 is pushed back by the force of the spring 93, and the hydraulic block 81 rotates to open the hole 45 in the fixed wall 44.

Next, at θ5, the solenoid valve 74 is opened by the output signal of the controller 61, and the solenoid valve 73 is closed, so that the pressure in the valve-closing oil chamber 43 decreases. the result.

The exhaust valve 40 begins to open due to the force acting on the exhaust valve 40 of Pz. At the same time, the output signal from the controller 61 causes the solenoid valve 72 to close and the solenoid valve 71 to open.

High pressure hydraulic oil acts on the valve opening oil chamber 42 . This ensures that the exhaust valve 40 opens.

Further, when the crank angle θ passes the bottom dead center BDC of the piston 11, an output signal from the controller 61 causes the valve oil chamber 4 to open.
2 decreases, the hydraulic pressure in the valve-closing oil chamber 43 increases, the valve begins to close, and the valve closes at θ6.

The above case has the following effects.

The device of the present invention does not require a large camshaft or cam as shown in FIG. 3, so the structure is simple and the cost can be significantly reduced.

In the present invention, when an outward-opening type exhaust valve 40 is used, it is necessary to prevent the exhaust valve 40 from opening even due to the high cylinder internal pressure P2 that acts while the valve is closed. By using the exhaust valve 40, the force that presses the exhaust valve 40 downward becomes large and it does not open.

Furthermore, the stroke of the hydraulic disc 82 of the hydraulic block 81 is limited to the clearance that allows the hydraulic block 81 to be inserted between the fixed wall 44 and the exhaust valve 40.

Since it can be made small, the amount of high pressure hydraulic oil consumed by the hydraulic block 81 is small.

Furthermore, when the valve is opened, the cylinder internal pressure P2 acts in a direction that accelerates the valve opening, so the pressure receiving area of the valve opening oil chamber 42 may be small.Furthermore, when the valve is closed, the cylinder internal pressure that acts on the exhaust valve 40 and the internal cylinder pressure that acts on the exhaust passage 19 Since the working gas pressures are the same, the pressure-receiving area of the valve-closing oil chamber 43 can also be small.

As a result, the amount of high-pressure hydraulic oil consumed as a whole is reduced, the power consumption of the hydraulic pump 54 is reduced, and the fuel efficiency of the engine as a whole can be improved.

Next, the opening/closing timing of the exhaust valve 40 is determined by the output signal of the controller 61, so when the two engines become low speed, the opening timing of the exhaust valve 40 is delayed and the effective stroke of the piston is increased to reduce fuel consumption. The opening/closing timing of the exhaust valve 40 can be changed depending on the operating state of the engine.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing a conventional exhaust valve hydraulic drive system, Figure 2 is an explanatory diagram showing a conventional exhaust valve hydraulic drive device;
The figure is a diagram showing the change in the pressure (P) of the hydraulic oil in the hydraulic cylinder and the exhaust valve rift (L) of the device shown in FIG. 1, and FIG. , FIG. 4 is a plan view showing a hydraulic block C1,) according to an embodiment of the present invention, FIG. 5 is a sectional view showing the hydraulic block of FIG. 4, and FIG.
The diagram shows the cylinder internal pressure and the exhaust valve ref of the device in Figure 3)
and FIG. 9 is a diagram showing the respective changes in the pressure Po in the hydraulic cylinder 91. 40...exhaust valve, 41. ...Pressure collar, 44...
・Fixed wall, 71, 72, 73.74, 75, 76.77
゜78...Solenoid valve, 81...Hydraulic block. Fang 3 figure 74 figure 5

Claims (1)

[Scope of Claims] 1. An exhaust valve formed in an outward-opening type that opens toward the outside of a combustion chamber, a fluid pressure cylinder in which a fixed piston is inserted in the middle of the valve stem of the exhaust valve, and the same fluid. A solenoid valve is provided in each of the supply path and discharge path of high-pressure fluid to the pressure cylinder and controls the opening and closing of each path. During the closing period of the exhaust valve, a hydraulic block is provided between a fixed wall provided on the upper part of the exhaust valve rod and the upper end of the exhaust valve rod, which is held by the force of the high-pressure fluid. Exhaust valve drive device for internal combustion engine.